Perhaps you should try some spelling variations:
lang van » dang van, tang van, hoang van
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, ban hanh
mang xa » lang xa, mang may, dang xay
va danh » va dinh, va dan, dia danh
cac hoc » cach hoc, cac hop, bac hoc
di cua » dai cua, doi cua, de cua
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
cua te » cua tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky ((mang xa) or (lang van)) hoi. hieu va cac hoc ((va hanh) OR (va danh)) di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((mang xa) OR (lang van)) hoi. hieu va cac hoc ((va hanh) OR (va danh)) di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky ((mang xa) or (lang van)) hoi. hieu va cac hoc ((va hanh) OR (va danh)) di cua te".
• Adding a wildcard symbol may retrieve word variants: te sac ky ((mang xa) or (lang van)) hoi. hieu va cac hoc ((va hanh) OR (va danh)) di cua te*.